ON THE PHYTOLACCA. SQ 



On the contrary, sliould it prove to be malic acid, it would 

 be at least the first example of malate of potash found abuu-f 

 dantly as a natural production 



Sect. ITI, 



Exnjninatian of the colouring matter contained in the herries of 

 the Phytolacca. 



The berries being bruised in a glass mortar with a certain The colouring 

 quantity of water, the filtered liquor was of a fine bright pur- 

 ple colour. I at first attempted to fix it on cloths, but soon 

 found its extreme fugaciousness. 



The juice of the Ijerries has a sweetish taste, leaving be- The juice of 

 hind a sensation of acrimony, Paper tinged blue with lit-^^^ ernes. 

 mus, and wetted with water, was reddened when dipped into 

 it ; but the blue was restored without the least alteration by 

 washing with a little warm water. 



At a moderate temperature it soon underwent the vinous Soon ferments, 

 fermentation. The wine produced was unpleasant to the ''''^^^^ ^^^» ^^^ 

 taste, but brandy may be obtained from it by distillation. ^ 



If a few drops of lime water be added to the juice, it soon Lime water 

 assumes a fine yellow colour; but the smallest quantity of ^^^^^ ^^ ^^' 

 acid soon restores its purple hue. If the yellow liquor have Any acid, 

 sufficient colour to write with it, breathing on the paper will 

 change .the yellow letters to purple; and so will even expo- 

 sure to the air, though less speedily. 



Sulphuretted hidrogen, or urine added in small quantity sulphuretted 

 to the yellow liquor, clianges it immediately purple. hid.ogen, or 



The deep yellow liquor produced by the combination of "/jg'pj^^p^jg^^''^*"^ 

 the purple of phytolacca with lime grovv^s lighter by the ad- Water dilutes 

 dition of water, and assumes the tint of chromate of })otash. the yellow, and 

 But if the quantity of water be still increased, the oriuinal I", j""^^^, ^"^"' 



*■ •^ O Illy Ifc^SlOr&i 



purple reappears. At fust I ascribed this effect to the car- t-^^e purple. 

 bonic acid, that might be contained in the water; but water 

 long boiled exhibits the same phenomenon. Hence I infer, 

 that water acts by weakening the effect of the lime in the 

 yellow liquor, which occasions it to return to purple. 



From what has been said it appears, that the yellow li- 

 quid affords a verj delicate te§t of the presence of acids; ofaciir:^ ^^" 



and 



